KR20050021245A - Electronic thermometer - Google Patents

Abstract

PURPOSE: An electronic thermometer is provided to measure a temperature within a short period of time with a high precision by combining initial information of a temperature increase curve with next information of the temperature increase curve. CONSTITUTION: An electronic thermometer(1) includes a temperature measurement section(2) for measuring the temperature, a calculation section(3) for predicting and calculating an equilibration temperature, a display section(4) for displaying the result of prediction, a power source(5) for supplying power to the calculation section(3) and the display section(4), and a power switch(6). The temperature measurement section(2) has a temperature sensor, such as a thermister. The calculation section(3) monitors the signal outputted from the temperature sensor of the temperature measurement section(2).

Description

Electronic thermometer {ELECTRONIC THERMOMETER}

The present invention relates to a predictive electronic thermometer.

Electronic thermometers are largely divided into two types. One is called actual expression. This is an electronic thermometer in which the temperature of the temperature measuring element in the temperature measuring part is displayed as it is. In such a measurement type thermometer, the temperature measurement part is placed in a measurement target such as the armpit or the mouth, and the temperature (equilibrium temperature) at the time when the temperature does not rise further is set to the body temperature. To measure the equilibrium temperature with an actual thermometer, it usually takes more than 5 minutes in the mouth and 10 minutes in the armpits. In a measurement formula, a buzzer sounds in the place where temperature rise became below a certain value, and the temperature measurement end may be made. In this case, the measurement ends in 3 to 5 minutes, and the measured body temperature is slightly lower than the actual equilibrium temperature.

There is also an electronic thermometer called a predictive equation. The predictive electronic thermometer calculates a correction amount by extracting the relationship between the characteristics of the temperature rise curve and the equilibrium temperature from a statistical method or a thermal conductivity equation, and adds the correction amount to the temperature value to predict and display the equilibrium body temperature (Patent Documents 1 to 4). Reference). In these predictive electronic thermometers, prediction results are displayed for 1 to 2 minutes from the start of measurement.

In the electronic thermometer of the prediction equations thus far, an equilibrium is calculated by analyzing curve approximation or the like based on a temperature and a temperature gradient at a certain time or assuming an expression of heat transfer when a micro object is heated. I was predicting the temperature. In this case, practically, the initial value of the temperature rise curve is not used, and only a portion showing a part after the time elapses for some time and a method of transferring the temperature from the inside of the living body to the surface is considered. That is, since the initial part of the temperature rise curve is susceptible to the initial state of the temperature measurement part or the skin surface, and these states are likely to change, the first part of the temperature rise curve was excluded from the calculation.

Patent Document 1: Japanese Patent Application Laid-open No. 52-75385

Patent Document 2: Japanese Patent Application Laid-open No. 55-78220

Patent Document 3: Japanese Patent Laid-Open No. 59-l87233

Patent Document 4: Japanese Patent Publication No. Hei 7-111383

However, since the method of the conventional electronic thermometer of the conventional prediction formula does not consider the influence of the measurement initial stage mentioned above, in general, the prediction precision became worse as the measurement time became short. For this reason, in order to predict with high precision, it is necessary to wait until the initial influence disappears, and the time elapsed until the desired effect disappears. For example, this type of thermometer required 60 seconds to 120 seconds for the prediction time.

This invention is made | formed in order to solve such a subject of the prior art, and the objective is to provide the electronic thermometer which can measure high-precision temperature in a short time.

MEANS TO SOLVE THE PROBLEM In order to achieve the said objective, this invention is an electronic thermometer which has a temperature measuring means, and measures a body temperature, Comprising: The 1st temperature change information obtained until a predetermined time progresses after starting temperature measurement, and the 2nd temperature change information obtained after that It is an electronic thermometer which predicts the equilibrium body temperature from.

In this way, since the equilibrium temperature can be predicted from the initial temperature change information from the start of measurement, high-precision temperature measurement can be performed in a short time.

The first temperature change information is preferably information obtained from about 20 seconds after the start of measurement.

Preferably, the first temperature change information is a physical quantity other than temperature.

Preferably, the first temperature change information indicates a duration of temperature rise, and the second temperature change information is a temperature gradient.

It is preferable that the 1st temperature change information which shows the duration of the said temperature rise is time until a temperature gradient value becomes a predetermined value from a peak.

Two temperature detection means arranged in the site | part which differs in a thermal characteristic, Comprising: The 1st temperature change information is a value obtained from the difference of the temperature detected by two temperature detection means, The 2nd temperature change information detects any one temperature. It is preferable that it is the temperature gradient obtained from a means.

It is preferable that the 1st temperature change information obtained from the said two temperature detection means is a value calculated | required from the linear relationship between the temperature detected by either temperature detection means, and the temperature detected by two temperature detection means. Do.

According to the present invention, it is possible to provide a thermometer which can measure body temperature with high accuracy in a short time.

(First embodiment)

EMBODIMENT OF THE INVENTION Hereinafter, with reference to drawings, the predictive electronic thermometer according to embodiment of this invention is demonstrated.

1 is a block diagram showing the basic configuration of a predictive electronic thermometer. The predictive electronic thermometer 1 mainly supplies power to the temperature measuring unit 2, the predictive calculating unit 3 for predicting and calculating the equilibrium body temperature, the display unit 4 for displaying the prediction result, the predictive calculating unit 3 and the display unit 4, and the like. The power supply 5 to be supplied and the power supply switch 6 which switch on / off of power supply are comprised. The temperature measurement part 2 has a temperature sensor, such as a thermistor, for example. The predictive calculating section 3 monitors the signal from the temperature sensor of the temperature measuring section 2 and predicts and calculates the equilibrium body temperature based on the temperature and the elapsed time information. The result calculated by the predictive calculating section 3 is sent to the display section 4, and the display section 4 displays the predicted body temperature.

2 shows a schematic configuration of the predictive electronic thermometers 10 and 11.

The predictive electronic thermometers 10 and 11 are provided with a body part 7 of a substantially rectangular parallelepiped and a rod-shaped probe 8 extending in the longitudinal direction from the longitudinal end of the body part 7. The display portion 4 and the power switch 6 are disposed on the main body 7 so as to be exposed to the surface. The temperature measurement part 2 is provided in the front-end | tip of the probe 8. As shown in FIG. The temperature sensor 21 is arrange | positioned at the inner surface of the temperature measurement part 2 formed in hollow shape, and heat is transmitted to the temperature sensor (temperature detection means) 21 from the outer surface of the temperature measurement part 2 ( (A) of FIG. 2). The temperature sensor 21 is electrically connected to the predictive calculating unit 3 arranged inside the main body unit 7, and the output of the temperature sensor 21 is input to the predictive calculating unit 3.

In addition, the structure of the temperature measurement part 2 is not limited to the above-mentioned thing, You may be provided with two temperature sensors, the 1st temperature sensor 211 and the 2nd temperature sensor 212. Here, the first temperature sensor 211 (temperature detecting means) and the second temperature sensor 212 (temperature detecting means) each have different thermal characteristics (thermal conductivity, specific heat, density, any one, or any two or three of them). Is arranged on the inner surface of the temperature measuring portion 2 formed in a hollow shape through the material having the combination of the two (heat insulating materials 221 and 222) (the arrangement of the heat insulating materials is the first temperature sensor 211 and the second temperature sensor 212). Since it is intended to change the thermal characteristics of the heat sink, only one of the heat insulating materials may be installed). Therefore, heat is transferred from the outer surface of the temperature measuring part 2 to the first temperature sensor 211 through the heat insulating material 221, and heat is transferred to the second temperature sensor 212 through the heat insulating material 222. The first temperature sensor 211 and the second temperature sensor 212 are electrically connected to the predictive calculating unit 3 disposed inside the main body 7, so that the first temperature sensor 211 and the second temperature sensor are electrically connected. The output of 212 is input to the prediction calculating section 3, respectively.

The time change in the temperature rise of the thermistor after starting measurement under the armpit or in the mouth is generally represented by a graph as shown in FIG.

Temperature rise type when micro object is heated to this rising curve

T (t): temperature at time t, Ts: temperature of heating element (bio temperature), T0: initial temperature of object, α: constant, approx. 20 sec. It can be seen that it is divided into (dashed line in Fig. 3).

It is considered that the portion of the thermistor from about 20 seconds from the start of the measurement in the temperature rise curve reflects the surface temperature of the living body, the probe initial temperature, and how the heat is transferred from the living body to the probe.

In the temperature rise curve of the thermistor, the portion after about 20 seconds from the start of the measurement indicates a state in which heat is transferred from the inside of the living body to the surface by the reaction of the living body, and the temperature change is different depending on the individual measurement targets. In the past prediction method, the temperature data of the part of a temperature rise curve about 20 second after the start of a measurement was used.

The initial surface temperature of the living body is changed to reflect the relationship between the core body temperature and the external environment. The way in which heat is transferred to the probe also changes depending on the person under test, the surface under test and the surface state of the probe, and the contact state between the object under test and the probe. In other words, even if the same person is measured, these conditions change from measurement to measurement, and so far, in a part where the change in the temperature rise curve is relatively stable after a sufficient time so as not to be affected by the temperature information of such a variable part. Temperature information was adopted. However, on the contrary, accuracy can be improved in a short time measurement by using the information of the core body temperature, the external environment, and the method of transferring heat to the probe, the surface state, and the contact state appearing in these initial temperature rise portions. This is information about the temperature change in the initial stage from the start of the measurement until a predetermined time elapses (e.g., for about 20 seconds from the start of the measurement), and how the heat is transferred to the core body temperature, the external environment, and the probe. The surface state and the contact state are shown, and the reflected information corresponds to the first temperature change information. On the other hand, as information about the temperature change after a predetermined time has elapsed since the start of measurement (for example, after about 20 seconds have elapsed from the start of measurement), it represents a state in which heat is transferred from the inside of the body to the surface by the reaction of the living body, The information to reflect corresponds to 2nd temperature change information. However, this predetermined time is not limited to about 20 seconds, but may be changed by various factors.

As an example of the parameter indicating the initial temperature rise state, in the type using one sensor, the time from the maximum value of the slope ΔT (t) of the temperature rise curve to a certain value (for example, 0.2) (in FIG. 4). (expressed as τ (sec)) can be used. This is a parameter indicating the degree of continuation of the temperature rise in the initial part.

In FIG. 5, the example of the specific equilibrium temperature prediction method using this is shown.

First, the clock is started at the start of the measurement (step 1), and the temperature T (t) is obtained from the output of the temperature sensor 21 (step 2).

Next, it is determined whether any of the conditions in which the temperature T (t) is 31 ° C or higher or T (t) -T (t-0.5) is 0.2 ° C or higher is satisfied (step 3). If at least one of these conditions is satisfied, the clock is reset (step 4). On the other hand, in step 3, if none of these conditions are satisfied, the process returns to step 2.

After the clock is reset in step 4, the temperature T (t) is again obtained from the output of the temperature sensor 21 (step 5). Then, the temperature gradient ΔT (t) = T (t) -T (t-2.0) is calculated from the difference between the temperature at that time and the data two seconds before the time (step 6). Further, it is determined whether or not the temperature gradient ΔT (t) at that time is smaller than the temperature gradient ΔT (t-0.1) before 0.1 second (step 7). In step 7, if the temperature gradient at that time is equal to or greater than the temperature gradient 0.1 seconds ago, the process returns to step 5. In step 7, when the temperature gradient at that time is smaller than the temperature gradient at 0.1 second, the value t of the clock at that time is substituted into tm (step 8).

Next, it is judged whether or not the temperature gradient ΔT (t) = T (t) -T (t-2.0) is smaller than 0.2 ° C (step 9). In step 9, if the temperature gradient ΔT (t) is equal to or greater than 0.2 ° C, the process returns to step 8. In step 9, when the temperature gradient ΔT (t) is smaller than 0.2 ° C, the value t of the clock at that time is substituted into tn (step 10).

Then T = tn-tm is calculated from tm and tn (step 11). Τ calculated in this manner is the time until the temperature gradient becomes less than 0.2 ° C from the peak value.

Next, the temperature gradient Δ5T (t) = T (t) -T (t-5) is calculated from the difference between the time point and the data 5 seconds before that point (step 12).

Using these values, the predicted equilibrium temperature Tb (t)

or

Calculate by (Step 13).

Tb (t) is used as follows. For example, by continuously calculating the value of Tb (t), it is determined whether the variation is smaller than a predetermined value (0.1 ° C) or whether a predetermined time elapses such as t = 30 seconds (step 14), If none of these conditions are satisfied, the process returns to step 12. When any one of these conditions is satisfied, the value of Tb (t) at that time is displayed on the display unit 4 as a predicted value (step 15). Here, A, B, C, and D (E, F, G) are constants determined by a statistical method by taking a large number of data in advance.

As an example of the conventional prediction method

The equation was considered, and this and the prediction precision by Formula (1) which is an example of this invention were compared. Times are cut out every 10 seconds, and the optimum ABCD (for equation (1)) and ABC (for equation (3)) are obtained for each hour, and the body temperature of 77 people is estimated using these values. 6.

Each coefficient in 30 seconds is

In formula (1), A = 0.725, B = 5.536, C = -0.0732, D = 10.857

In equation (3), A = 0.705, B = 4.815, and C = 11.123

It was.

As shown in Fig. 6, when the equation (1) of the present invention is used, the accuracy equivalent to the time point after which time has elapsed after 30 seconds from the start of measurement is obtained. In contrast, in the conventional method using the equation (3), 50 seconds or more have elapsed since the start of measurement until the same precision can be obtained. As described above, according to the present invention, a high-precision body temperature measurement can be performed in a short time compared with the conventional electronic thermometer of the predictive formula.

Also in the case of the electronic thermometer which has two temperature sensors shown in FIG.2 (b), as a parameter which shows the initial temperature rise state, the 1st temperature sensor 211 and the 2nd temperature sensor 212 at the same time are shown. It is also possible to use the time (indicated by tau (sec) in Fig. 7) until the temperature difference Δ12T (t) = T1 (t) -T2 (t) of the maximum value becomes a certain value (for example, 0.5). In this case, the equilibrium temperature prediction method replaces ΔT (t) in the flowchart shown in FIG. 5 with Δ12T (t). As shown in Fig. 7, Δ12T (t) is sufficiently stabilized after about 30 seconds have elapsed from the start of measurement, so that even if this value is used as a parameter, accurate prediction can be made in a short time.

In addition to the above, examples of the parameter indicating the increase in the initial temperature may be employed such as the maximum value of the derivative, the time until the derivative becomes the maximum value, or the like.

(2nd embodiment)

As shown in FIG. 2B, in the case of the electronic thermometer 11 using two temperature sensors, the equilibrium body temperature can be predicted using other parameters. Since the structure of the electronic thermometer 11 was demonstrated in 1st Embodiment, the prediction method is demonstrated below.

In the electronic thermometer 11 having two temperature sensors, an initial characteristic value is obtained by utilizing a linear relationship between the temperature difference between the first temperature sensor 211 and the second temperature sensor 212 and the temperature at that time. In other words, the difference Δ12T (t) between the temperature value T1 (t) of the first temperature sensor 211 and the temperature value T2 (t) of the second temperature sensor 212 and the temperature T1 (t) at that time are for a certain time. After passing

A linear relationship that satisfies is satisfied (FIG. 8). H or m at this time is used as a characteristic value.

9 shows a specific equilibrium temperature prediction method of the electronic thermometer 11 having two temperature sensors. Here, the case of using m is demonstrated.

First, at the same time as the measurement starts, the clock is started (step 21), time-series temperature data of the first temperature sensor 211 and the second temperature sensor 212 are acquired, and the temperature T (t) is obtained from either output. (Step 22).

Then, it is determined whether any one of the conditions in which the temperature T (t) is 31 ° C or higher or T (t) -T (t-0.5) is 0.2 ° C or higher is satisfied (step 23). If either of these conditions is met, the clock is reset (step 24). On the other hand, in step 23, if none of these conditions are satisfied, the process returns to step 22.

After the clock is reset in step 23, the temperature T2 (t) is obtained from the output of the temperature T1 (t) and the temperature of the second temperature sensor from the output of the first temperature sensor (step 25). Then, the temperature difference Δ12T (t) = T1 (t) − between the temperature T1 (t) detected by the first temperature sensor 211 and the temperature T2 (t) detected by the second temperature sensor 212 at that time. T2 (t) is calculated (step 26).

M and H satisfying m = T1 (t) -HΔ12T (t) are calculated from the plurality of T1 (t) and Δ12T (t) (step 27). Specifically, for example, when data is acquired at an interval of 1 second and t seconds have elapsed,

M and H are calculated by the system of equations, and m and H are defined as m (t) parameters. Continue these calculations sequentially.

M (t) obtained in this way becomes a constant value in about 10 seconds as shown in FIG. This constant value is adopted as m. Specifically, it is determined whether or not the absolute value of the difference between m (t) at that time and m (t-1) 1 second before that time is less than 0.1 (step 28). In step 28, when the absolute value of the difference between m (t) and m (t-1) is 0.1 or more, the process returns to step 25. On the other hand, in step 28, when the absolute value of the difference between m (t) and m (t-1) is smaller than 0.1, m (t) at that point of time is m (step 29).

Next, the temperature gradient Δ12T (t) = T (t) -T (t-5) is determined from the difference between the time point and the data, for example, five seconds before that point.

Using these,

or

Calculate Tb from. For example, Tb (t) continuously calculates the value of Tb (t), and the value Tb (t) at that time and the absolute value of the value Tb (t-1) 1 second before that time (0.1 ° C) ), Or whether or not a predetermined time elapses, such as t = 30 seconds (step 31). In step 31, if none of these conditions are satisfied, the process returns to step 30. On the other hand, in step 31, when any one of these conditions is satisfied, the value of Tb (t) at that time is displayed on the display unit 4 as a predicted value (step 32). Where I, J, K, L (N, O, P) are predetermined constants.

As described above, by combining the initial information of the temperature rise curve and the subsequent information, accurate prediction is possible in a short time around 30 seconds.

According to the electronic thermometer of the present invention, high-precision temperature measurement can be performed in a short time.

1 is a block diagram showing the basic configuration of a predictive electronic thermometer according to an embodiment of the present invention.

2 (a) and 2 (b) are diagrams showing the schematic configuration of a predictive electronic thermometer of one sensor and two sensors, respectively.

3 is a graph showing the time change of the temperature rise of the temperature sensor from the start of measurement.

4 is a graph showing the time change of the temperature rise of the temperature sensor and the time change of the slope of the temperature rise curve.

Fig. 5 is a flowchart showing a method of predicting an equilibrium temperature using a slope of a temperature rise curve of a temperature sensor as a parameter.

6 is a graph showing a comparison result between an equilibrium temperature prediction method according to the present invention and a conventional method.

Fig. 7 is a graph showing the time change of the temperature value T1 (t) of the first sensor, the temperature value T2 (t) of the second sensor, and the difference ΔT (t) between T1 (t) and T2 (t).

8 is a graph showing a relationship between a difference ΔT (t) between a temperature value T1 (t) of a first sensor and a temperature value T2 (t) of a second sensor and a temperature T1 (t) at that time.

9 is a flowchart illustrating a method of predicting an equilibrium temperature in an electronic thermometer of two sensors.

Fig. 10 is a graph showing the time change of the temperature value T1 (t) of the first sensor and the temperature values T2 (t) and m (t) of the second sensor.

<Explanation of symbols for the main parts of the drawings>

1, 10, 11: electronic thermometer

2: temperature measuring part

3: Predictive computing unit

4: display unit

5: power

6: power switch

21: temperature sensor

211: first temperature sensor

212 second temperature sensor

221, 222: insulation

Claims (7)

As an electronic thermometer which has a temperature measuring means and measures a body temperature, An electronic thermometer that predicts an equilibrium body temperature from the first temperature change information obtained until a predetermined time elapses after the start of temperature measurement and the second temperature change information obtained thereafter. The electronic thermometer of claim 1, wherein the first temperature change information is information obtained from a measurement start until about 20 seconds have elapsed. The electronic thermometer of claim 2, wherein the first temperature change information is a physical quantity other than temperature. 4. The electronic thermometer according to claim 3, wherein said first temperature change information is indicative of a duration of temperature rise and said second temperature change information is a temperature gradient. The electronic thermometer according to claim 4, wherein the first temperature change information indicating the duration of the temperature rise is a time from a peak to a predetermined value. The method according to claim 2, further comprising two temperature detecting means disposed at different sites with different thermal characteristics, wherein the first temperature change information is a value obtained from a difference in temperature detected by the two temperature detecting means, and the second temperature change. The electronic thermometer in which the information is a temperature gradient obtained from any one of the temperature detection means. The first temperature change information obtained from the two temperature detecting means is a linear relationship between the temperature detected by either of the temperature detecting means and the difference between the temperature detected by the two temperature detecting means. Electronic thermometer which is a value calculated from.